TW202104650A - Plasma densification within a processing chamber - Google Patents

Abstract

A system and method for forming a film includes generating a plasma in a processing volume of a processing chamber to form the film on a substrate. The processing chamber may include a gas distributor configured to generate the plasma in the processing volume. Further, a barrier gas is provided into the processing volume to form a gas curtain around a plasma located in the processing volume. The barrier gas is supplied by a gas supply source through an inlet port disposed along a first side of the processing chamber. Further, an exhaust port is disposed along the first side of the processing chamber and the plasma and the barrier gas is purged via the exhaust port.

Description

Densification of plasma in the processing chamber

The embodiments of the present disclosure generally relate to the deposition of thin films on semiconductor substrates.

Plasma-enhanced chemical vapor deposition (PECVD) may be used to form one or more films on substrates used in semiconductor device manufacturing. In many cases, when PECVD is performed, plasma is generated in the processing chamber to form one film or multiple films on the substrate. In addition, the uniformity of one or more parameters of the film corresponds to the uniformity of the density of the plasma. Therefore, any difference in plasma density may result in a change in one or more parameters of a thin film or multiple thin films. In one example, non-uniform plasma density can produce films with non-uniform edge-to-edge thicknesses, which can make processed substrates unsuitable for use in semiconductor device manufacturing. Therefore, the yield may decrease, and the manufacturing cost may increase.

Therefore, there is still a need in the art for improved methods for forming thin films on semiconductor substrates and hardware components.

In one embodiment, a method for forming a film includes the following steps: generating a plasma in a processing volume of a processing chamber to form the film on a substrate, An inlet port on a first side introduces a barrier gas into the processing volume of the processing chamber to create a gas curtain along one or more edges of the substrate, and by following a first side of the processing chamber An exhaust port on one side removes the plasma and the barrier gas.

In one embodiment, a processing chamber includes: a substrate support configured to support a substrate in a processing volume of the processing chamber, and a gas inlet port along the A first side of the processing chamber is provided, and an exhaust port is provided along the first side of the processing chamber. The gas inlet port is configured to be coupled to a gas supply source configured to introduce a barrier gas into the processing volume of the processing chamber to generate a gas curtain along one or more edges of the substrate.

In one embodiment, a processing chamber includes: a gas distributor, a substrate support, a gas inlet, a gas supply source, and an exhaust port. The gas distributor is configured to generate a plasma in a processing volume of the processing chamber by ionizing a processing gas. The substrate support is configured to support a substrate in a processing volume of the processing chamber. The gas inlet port is arranged along a first side of the processing chamber. The gas supply source is coupled to the gas inlet port and is configured to introduce a barrier gas into the processing volume of the processing chamber to generate a gas curtain along one or more edges of the substrate. The exhaust port is provided along the first side of the processing chamber.

Semiconductor devices can be produced by forming one or more films on a substrate, and can include films including silicon, nitride, and oxide, and so on. The processing chamber used to process the substrate may be configured to perform chemical vapor deposition (CVD) including plasma enhanced CVD (PECVD), plasma enhanced atomic layer deposition (PEALD), or physical vapor deposition ( PVD)) operation. The quality of the film on the substrate may be negatively affected based on the difference and non-uniformity of the plasma density of the plasma above the substrate in the processing chamber. The difference in plasma density within the processing volume of the processing chamber can negatively affect the edge-to-edge uniformity of the film formed on the substrate. In addition, any unevenness of the film may result in a decrease in yield, thereby increasing the manufacturing cost of the semiconductor device.

Using the systems and methods discussed in this article, the uniformity of the plasma density within the processing volume (especially the plasma on the substrate) can be significantly improved. For a particular procedure, uniformity can be improved, for example, by introducing a barrier gas into the processing volume to create a gas curtain that reduces the dispersion of plasma within the processing volume. The reduced dispersion of the plasma within the processing volume increases the uniformity of the plasma above the substrate. In various embodiments, the reduced dispersion of plasma in the processing volume (e.g., increased densification of plasma in the processing volume compared to processing systems that do not include techniques to reduce the dispersion of plasma ) Increases the deposition rate by approximately 20 percent. In addition, due in part to the increased deposition uniformity of the formed film, reducing the dispersion of the plasma can positively adjust the film characteristics (eg, refractive index (n), stress, and extinction coefficient (k)).

Figure 1 illustrates a schematic cross-sectional view of a processing chamber 100 according to one implementation described herein. The processing chamber 100 is a PECVD chamber, but it can also be another plasma enhanced processing chamber. The processing chamber 100 has a chamber main body 102, a substrate support 104 disposed inside the chamber main body 102, and a cover assembly 106 coupled to the chamber main body 102 and enclosed in the processing volume 120 of the substrate support 104. The substrate support 104 is configured to support the substrate 154 thereon during processing. The substrate 154 is provided to the processing volume 120 via the opening 126. Although the embodiment of FIG. 1 is directed to a PECVD chamber, the cover assembly 106 and the substrate support 104 of FIG. 1 can be used with other processing chambers that utilize plasma generated in the processing volume 120.

The gas supply source 111 includes: one or more gas sources. The gas supply 111 is configured to deliver one or more gases from the one or more gas sources to the processing volume 120. Each of the one or more gas sources provides a process gas (e.g., argon, hydrogen, or helium) that can be ionized for plasma formation. For example, one or more of the carrier gas and the ionizable gas may be provided to the processing volume 120 along with the same or more precursors. When processing a 300 mm substrate, the processing gas is introduced into the processing chamber 100 at a flow rate of from about 6500 sccm to about 8000 sccm, from about 100 sccm to about 10,000 sccm, or from about 100 sccm to about 1000 sccm. Alternatively, other flow rates can be used. In some examples, a remote plasma source may be used to deliver plasma to the processing chamber 100 and may be coupled to the gas supply source 111.

The gas distributor 112 has openings 118 for allowing the processing gas (or several processing gases) to enter the processing volume 120 from the gas supply source 111. The processing gas is supplied to the processing chamber 100 through the pipe 114, and the processing gas enters the gas mixing area 116 before flowing through the opening 118.

The electrode 108 is disposed adjacent to the chamber body 102 and separates the chamber body 102 from other components of the cover assembly 106. The electrode 108 is part of the cover assembly 106, but may be a separate sidewall electrode. The electrode 108 may be a ring-shaped or ring-shaped member, and may be a ring-shaped electrode. The electrode 108 may be a continuous ring around the perimeter of the processing chamber 100 (which surrounds the processing volume 120), or may be discontinuous at selected locations. The electrode 108 may also be a perforated electrode (for example, a perforated ring or mesh electrode). The electrode 108 may also be a plate electrode (for example, an auxiliary gas distributor).

The electrode 108 is coupled to the power source 128. The power source 128 is a radio frequency (RF) power source electrically coupled to the electrode 108. In addition, the power source 128 provides power between about 100 Watt and about 3,000 Watt at a frequency of about 50 kHz to about 13.6 MHZ. Alternatively, the power source 128 may be pulsed during various operations. The electrode 108 and the power source 128 facilitate additional control of the plasma formed within the processing volume 120.

The substrate support 104 includes one or more metal materials or ceramic materials, or is formed from one or more metal materials or ceramic materials. Exemplary metal materials or ceramic materials include: one or more metals, metal oxides, metal nitrides, metal oxynitrides, or any combination thereof. For example, the substrate support 104 may include: aluminum, aluminum oxide, aluminum nitride, aluminum oxynitride, or any combination thereof, or aluminum, aluminum oxide, aluminum nitride, aluminum oxynitride, or any combination thereof In the formation.

The electrode 122 is embedded in the substrate support 104, but may alternatively be coupled to the surface of the substrate support 104. The electrode 122 is coupled to the power source 136. The power source 136 is DC power, pulsed DC power, radio frequency (RF) power, pulsed RF power, or any combination thereof. The power source 136 is configured to use a driving signal to drive the electrode 122 to generate plasma in the processing volume 120. The driving signal may be one of a DC signal and a varying voltage signal (for example, an RF signal). In addition, the electrode 122 may alternatively be coupled to the power source 128 (instead of the power source 136), and the power source 136 may be omitted.

The power source 128 and the power source 136 generate plasma in the processing volume 120. The RF field is established by driving at least one of the electrode 108 and the electrode 122 with a driving signal to promote the formation of capacitive plasma in the processing volume 120. The presence of the plasma facilitates the processing of the substrate 154 (for example, the deposition of a film on the surface of the substrate 154).

One or more gas inlet ports 152 are coupled to the gas supply source 153 and are provided in the bottom chamber wall 101 of the processing chamber 100 under the substrate support 104. The gas supply source 153 provides one or more gases to the processing volume 120 through the gas inlet port 152. For example, the gas supply source 153 provides barrier gas to the processing volume 120. The barrier gas is any gas that does not significantly interact (eg, mix) with the plasma, and can form a gas curtain around the substrate 154 to slow the dispersion of the plasma in the processing volume 120. For example, the gas that does not significantly interact with the plasma can be any gas that at least partially slows the dispersion of the plasma within the processing volume 120. Furthermore, the barrier gas can be any gas that reduces the formation of parasitic plasma. In addition, the barrier gas may be an inert gas. Alternatively, or additionally, the barrier gas may be helium, hydrogen, nitrogen, argon, oxygen, or nitrogen oxides (NO _x) any one of the like. The gas supply source 153 controls the type of barrier gas and the flow rate of the barrier gas entering the processing volume 120, thereby controlling one or more parameters of the gas curtain generated by the barrier gas. In addition, the barrier gas may act as a purge gas to facilitate the removal of gas, plasma, or by-products from the processing volume 120.

The shield (or ring) 160 guides the barrier gas to flow along the periphery of the substrate support 104 and the periphery of the substrate 154. For example, the shield 160 may control the flow of the barrier gas so that the barrier gas flows along the periphery of the substrate support 104 and the periphery of the substrate 154 before being dispersed in the processing volume 120. The shield 160 is coupled to the chamber wall 101. Alternatively, the shield 160 may be coupled to another chamber wall of the processing chamber 100. As illustrated by the example, the shield 160 circumscribes the substrate support 104.

The exhaust port 156 is coupled to the vacuum pump 157 and is provided along the same wall of the processing chamber 100 (for example, the chamber wall 101) (the same as the gas inlet port 152). Alternatively, as long as it does not negatively affect the flow of the barrier gas along the periphery of the substrate 154, the exhaust port 156 may be provided along the other wall of the processing chamber 100, thereby preventing the formation of the gas curtain 214 in FIG. 2 . The vacuum pump 157 uses the exhaust port 156 to remove excess process gas or by-products from the process volume 120 during and/or after the process.

FIG. 2 illustrates a schematic cross-sectional view of the processing chamber 100 according to one or more embodiments, and how gas flows in the processing chamber 100 and creates a gas curtain in the processing chamber 100. One or more processing gases flow from the gas supply 111 along the path 210 and through the gas distributor 112 to facilitate the processing of the substrate 154. The processing gas is converted into plasma in the plasma region 220 above the substrate 154 in the processing volume 120 in FIG. 1. The gas inlet port 152 provides a barrier gas to act as a purge gas to help remove excess processing gas or by-products from the processing volume 120 through the exhaust port 156 during and/or after processing, And an air curtain 214 is also generated. The barrier gas flows along path 212 (e.g., paths 212a and 212b). As the barrier gas is reduced, the plasma is dispersed in the entire processing chamber. For example, due to the difference in electronegativity between the barrier gas and the processing gas, the barrier gas may not interact (e.g., mix). In addition, reducing the dispersion of plasma in the entire processing chamber increases the uniformity of the plasma density in the plasma region 220 above the substrate. For example, the density of the plasma along the edge of the substrate 154 may be similar to the density of the plasma near the center of the substrate 154. Furthermore, a film formed from a plasma having a more uniform density can have a more uniform edge-to-edge thickness or k value. For example, the thickness of the film and/or the k value of the film along the edge of the substrate 154 may be similar to the thickness of the film and/or the k value of the film near the center of the substrate 154. In addition, the deposition rate of a film formed from a plasma having a more uniform density may be about 20% higher than that of a film formed from a plasma having no uniform density, while maintaining similar film quality.

The air curtain 214 acts as a choke to reduce the dispersion of plasma in the processing volume 120, thereby densifying the plasma in the plasma region 220 and increasing the density of the plasma in the plasma region 220 The uniformity. In addition, an air curtain may be generated around the entire periphery of the substrate 154. Reducing the dispersion of the plasma in the processing volume will trap the plasma and increase the uniformity of the plasma in the plasma region 220. Therefore, the deposition uniformity of the corresponding film is increased. Furthermore, reducing the dispersion of the plasma will increase the quality of the plasma by increasing the deposition rate and/or k value of the film formed on the substrate. In addition, the cross-sectional shape of the edge-to-edge thickness profile of the film formed on the substrate in the processing chamber using the barrier gas is greater than the edge-to-edge thickness of the film formed on the substrate in the processing chamber that does not use the barrier gas. The cross-sectional shape of the profile is flat. In addition, the k value profile of the film formed on the substrate in the processing chamber that uses the barrier gas is larger than the k value profile of the film formed on the substrate in the process chamber that does not use the barrier gas.

The flow rate and type of the barrier gas may correspond to an amount that prevents the plasma from being dispersed in the processing volume 120, and may correspond to the uniformity of the plasma density. For example, a higher flow rate can provide a greater reduction in the amount of plasma dispersed and a greater increase in the uniformity of the plasma density (compared to a lower flow rate). The flow rate of the barrier gas may be in the range of about 100 sccm to about 5000 sccm. In an example embodiment, when the flow rate of the processing gas is about 3 liters, the flow rate of the barrier gas may be in the range of about 100 sccm to about 1000 sccm (which depends on the type of processing gas used) . In addition, the flow rate of the barrier gas may be less than the flow rate of the processing gas. For example, the flow rate of the barrier gas may be a percentage of the flow rate of the processing gas. An example flow rate of the barrier gas may be in the range of about 10% to about 80% of the process gas. Alternatively, percentages of less than 10% and greater than 80% can be used.

Furthermore, different types of barrier gases can prevent different amounts of plasma from dispersing and provide a greater increase in the uniformity of the plasma density within the processing volume 120. In addition, the flow rate of the barrier gas may be based on at least one of the following: the type of barrier gas used, the type of gas used to generate plasma, the flow rate of the processing gas, and the prevention of plasma dispersion. the amount. For example, the flow rate of the first barrier gas used for the first processing gas may be different from the flow rate of the first barrier gas used for the second processing gas. Furthermore, the flow rate of the first barrier gas used for the first processing gas may be different from the flow rate of the second barrier gas used for the first processing gas. The type of barrier gas can be selected based on the electronegativity of the process gas (or several process gases). For example, the barrier gas may be selected based on the difference in electronegativity between the processing gas and the barrier gas. In addition, the barrier gas can be selected to maximize the difference in electronegativity between the process gas and the barrier gas. Furthermore, the barrier gas can be selected according to the driving signal used to convert the process gas into plasma. For example, the barrier gas may be selected so that in the presence of a driving signal used to convert the process gas into plasma, the barrier gas does not ionize (eg, ignite) into plasma.

Figure 3 illustrates a top view of the air curtain 214 according to one or more embodiments. As illustrated in FIG. 3, the substrate 154 is surrounded by an air curtain 214. Alternatively, the air curtain 214 may partially surround the substrate 154. In addition, the thickness of the air curtain 214 may be substantially uniform or non-uniform. Additionally, or alternatively, the distance between the substrate 154 and the air curtain 214 may be substantially uniform or non-uniform.

As discussed herein, the film deposition operation may include the formation of one or more films on the substrate 154 disposed on the substrate support 104. FIG. 4 is a flowchart of a method 400 for processing a substrate according to one or more embodiments. The method 400 can be utilized to form one or more films on the substrate 154. For example, the substrate 154 may be disposed in the processing chamber 100 to form one or more films on the substrate 154.

At operation 410, plasma is generated in the processing volume 120 of the processing chamber 100. For example, one or more processing gases may be introduced into the processing chamber 100 by the gas supply source 111. The processing gas may include: at least one precursor gas, ionizable gas, and carrier gas, and one or more of the processing gas may be ionized to form plasma. For example, the electrode 122 may be driven by a power source 136 and an RF signal to ionize the processing gas (or several processing gases) into plasma. In addition, in the presence of plasma, the precursor gas can be utilized to form a film on the substrate. For example, the power sources 128 and 136 may be driven while the processing gas is introduced into the processing chamber 100 to generate plasma.

At operation 420, a barrier gas is introduced into the processing volume 120 of the processing chamber 100. For example, the barrier gas may be introduced into the processing volume 120 of the processing chamber 100 by the gas supply source 153 through the gas inlet port 152. The barrier gas can create a gas curtain (eg, gas curtain 214) that reduces the dispersion of plasma within the processing volume 120, thereby increasing the uniformity of the plasma density above the substrate 154. For example, the air curtain 214 can function as a choke to reduce the amount of parasitic plasma formed near the edge of the substrate 154 and increase the uniformity of the plasma density in the plasma region 220. Therefore, the edge-to-edge uniformity of one or more parameters of the film formed on the substrate 154 is also increased. For example, the edge-to-edge uniformity of the thickness of the film can be increased. Alternatively, or additionally, the edge-to-edge uniformity of the k value of the film can be increased. In addition, the increase in density uniformity can produce local plasma densification, which can improve the plasma quality and increase the deposition rate of the corresponding film, thereby improving one or more parameters of the film.

The flow rate of the barrier gas can be selected according to the type of the processing gas, the type of the barrier gas, and/or the flow rate of the processing gas. The flow rate of the barrier gas may be less than the flow rate of the process gas. In addition, the flow rate of the barrier gas may be a percentage of the flow rate of the processing gas. Additionally, or alternatively, the flow rate of the barrier gas may correspond to the amount by which the plasma is densified above the substrate 154. For example, the flow rate of the barrier gas can be adjusted to maintain a substantially uniform plasma density above the substrate 154. For example, the flow rate of the barrier gas can be adjusted to maintain a plasma density within about 5% of the optimal uniformity. In addition, when the uniformity of the plasma density is less than the first critical value and when the increased plasma density is greater than the second critical value, the flow rate of the barrier gas can be increased. When discussing 2 critical values, alternatively, more than 2 critical values or less than 2 critical values can be used.

At operation 430, the plasma and barrier gas are removed from the processing chamber 100. For example, the exhaust port 156 may be coupled to a vacuum pump 157, and the vacuum pump 157 uses the exhaust port to remove excess processing gas or by-products from the processing volume 120 during and/or after processing. .

Therefore, using the system and method discussed in this article, by introducing the barrier gas, the uniformity of the plasma density within the processing volume of the processing chamber can be increased, thereby increasing the corresponding film or several films produced on the substrate. Uniformity of the film. In addition, the deposition rate of the film is increased. Therefore, the yield of the corresponding semiconductor device can be increased, and the manufacturing cost can be reduced. The barrier gas can create a gas curtain, or choke, to reduce the dispersion of the plasma within the processing volume, thereby increasing the uniformity of the plasma density above the substrate.

Although the foregoing is about the embodiments of the present disclosure, other and additional embodiments of the present disclosure can be conceived without departing from its basic scope, and its scope is determined by the scope of subsequent patent applications.

100: processing chamber 101: bottom chamber wall 102: Chamber body 104: substrate support 106: cover assembly 108: Electrode 111: gas supply source 112: Gas distributor 114: pipe 116: Gas mixing area 118: open 120: processing volume 122: Electrode 126: opening 128: Power 136: power source 152: Gas inlet port 153: Gas supply source 154: Substrate 156: Exhaust Port 157: Vacuum Pump 160: shield 210: Path 212: Path 214: Air Curtain 220: Plasma area

In order to make it possible to understand in detail the manner in which the features of the present disclosure are quoted in the foregoing, a more specific description of the present disclosure (which is briefly summarized in the foregoing) can be obtained by referring to the embodiments, some of which are The examples are illustrated in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate exemplary embodiments, and thus are not considered as limiting the scope thereof, and other equally effective embodiments may be allowed.

Figures 1 and 2 are schematic cross-sectional views of a substrate processing system according to one or more embodiments.

Figure 3 illustrates a top view of a substrate and air curtain according to one or more embodiments.

Figure 4 illustrates a flowchart of a method of forming a film according to one or more embodiments.

To facilitate understanding, the same element symbols have been used where possible to designate the same elements that are shared by the drawings. It is considered that the elements and features of one embodiment can be advantageously incorporated into other embodiments without further elaboration.

Domestic deposit information (please note in the order of deposit institution, date and number) no Foreign hosting information (please note in the order of hosting country, institution, date and number) no

100: processing chamber

101: bottom chamber wall

102: Chamber body

104: substrate support

106: cover assembly

108: Electrode

111: gas supply source

112: Gas distributor

114: pipe

116: Gas mixing area

118: open

120: processing volume

122: Electrode

126: opening

128: Power

136: power source

152: Gas inlet port

153: Gas supply source

154: Substrate

156: Exhaust Port

157: Vacuum Pump

160: shield

Claims (20)

A method for forming a film, the method includes the following steps: Generating a plasma in a processing volume of a processing chamber to form the film on a substrate; A barrier gas is introduced into the processing volume of the processing chamber by an inlet port from a first side of the processing chamber to along the processing volume during a time interval overlapping with the generation of a plasma in the processing volume One or more edges of the substrate to create an air curtain; and The plasma and the barrier gas are removed by an exhaust port of the processing chamber. The method of claim 1, wherein the step of generating the plasma includes the step of ionizing a processing gas flowing through a gas distributor of the processing chamber. The method of claim 2, wherein the substrate is disposed on a substrate support of the processing chamber, and wherein the substrate is disposed between the gas distributor and the first side. The method according to claim 2, wherein the flow rate of the barrier gas is based on at least one of the flow rate of the processing gas, the type of the barrier gas, and the type of the processing gas. The method according to claim 1, wherein the barrier gas is one of helium, hydrogen, nitrogen, argon, oxygen, or nitrogen oxide. The method according to claim 1, wherein the barrier gas is an inert gas. The method of claim 1, wherein generating the gas curtain along the one or more edges of the substrate increases a uniformity of a density of the plasma above the substrate. The method of claim 7, wherein increasing the uniformity of the density of the plasma above the substrate increases the uniformity of a thickness of the film formed on the substrate. A processing chamber comprising: A gas distributor configured to generate a plasma in a processing volume by ionizing a processing gas; A substrate support configured to support a substrate in the processing volume; A gas inlet port, the gas inlet port being arranged along a first wall of the processing chamber; and A gas supply source coupled to the gas inlet port and configured to introduce a barrier gas into the processing volume along the time interval during which the plasma is generated in the processing volume overlap One or more edges of the substrate create an air curtain. The processing chamber according to claim 9, wherein the first wall of the processing chamber is opposite to the gas distributor. The processing chamber of claim 9, wherein the gas supply source is configured to be based on at least one of a flow rate of the processing gas, the type of the barrier gas, and the type of the processing gas, at the flow rate To supply the barrier gas. The processing chamber according to claim 9, wherein the barrier gas is one of helium, hydrogen, nitrogen, argon, oxygen, or nitrogen oxide. The processing chamber according to claim 9, wherein the gas curtain is generated along the one or more edges of the substrate to increase a uniformity of a density of the plasma above the substrate. The processing chamber according to claim 9, further comprising: A shield disposed in the processing volume and surrounding the substrate support, the shield configured to control a flow of the barrier gas; and An exhaust port is provided along the first wall of the processing chamber. A processing chamber comprising: A gas distributor configured to provide a processing gas to a processing volume for generating a plasma; A substrate support configured to support a substrate in the processing volume; A gas inlet port, the gas inlet port being arranged along a first wall of the processing chamber; A gas supply source configured to introduce a barrier gas into the processing volume of the processing chamber to be along a portion of the substrate during a time interval overlapping with the generation of the plasma in the processing volume Or multiple edges create an air curtain; A shield disposed in the processing volume and surrounding the substrate support, the shield configured to control a flow of the barrier gas to form the gas curtain; and An exhaust port is provided along the first wall of the processing chamber. The processing chamber according to claim 15, further comprising: A power supply configured to generate the plasma in an internal region of the processing chamber by ionizing the processing gas. The processing chamber according to claim 16, wherein the substrate is disposed between the gas distributor and the first wall of the processing chamber. The processing chamber according to claim 15, wherein the gas curtain is generated along the one or more edges of the substrate to increase a uniformity of a density of the plasma above the substrate. The processing chamber of claim 18, wherein increasing the uniformity of the density of the plasma above the substrate increases the uniformity of a thickness of a film formed on the substrate. The processing chamber of claim 15, wherein the gas supply source is configured to be based on at least one of a flow rate of the processing gas, a type of the barrier gas, and a type of the processing gas, at the flow rate Supply the barrier gas.

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